Conventionally, a waterproof structure as disclosed in JP 2003-17476A (Patent Document 1) is known as a structure for waterproofing terminal portions of a multicore cable. In this structure, a tubular member is fitted around a front end of a sheath of the multicore cable from which a plurality of electrical wires are drawn out, and this tubular member is filled with a sealing material such as a silicone-based adhesive.
In the above-described multicore cable, first, the front end of a nozzle is inserted into a gap between the sheath and the tubular member, and a sealing material is injected from the front end of the nozzle, the front end of the nozzle is then inserted between a plurality of electrical wires, and the sealing material is injected from the front end of this nozzle between the plurality of electrical wires. Accordingly, the electrical wires and the sheath are sealed, and the electrical wires are sealed.